Method for producing a novel crimped yarn and fabric



.Jan. 17, 1967 A. H. AGETT ETAL 3,298,079

METHOD FOR PRODUCING A NOVEL CRIMPED YARN AND FABRIC Filed May 24, 19652 Sheets-Sheet 1 THIS INVEN'HON FIG. I.

PRIOR ART FIG. 3.

ALBERT H. AGETT INVENTORS Y QMM ATTORNEYS WILLIAM L. ASPY 3Y2 Jan. 17,1967 Filed May 24. 1965 TOW FROM SPINNING CABINETS SPECIFIC VOLUME-CUBICINCHES PER LB.

A. H. AGETT ETAL 3,298,079

METHOD FOR PRODUCING A NOVEL CRIMPED YARN AND FABRIC 3 Sheets-Sheet 2PREHEAT ROLL SECOND DRAFT ROLL FIRST DRAFT 28 ROLL THIRD DRAFT ROLLUNBULKED BULKED BY HEAT TREATMENT PRIOR ART HIGH SHRINK HIGH SHRINKINVENTORS MODACRYLIC UNMODIFIED MODACRYLIC Q I YARN POLYACRYLO- YARN BYW NITRILE YARN 7W ATTORNEYS WILLIAM L. ASPY United States Patent M3,298,079 METHUD FOR PRGDUCING A NOVEL CRIMPED YARN AND FABRIC Albert H.Agett and William L. Aspy, J12, both of Kingsport, Tenn., assignors toEastman Kodak Company, Rochester, N.Y., a corporation of New JerseyFiled May 24, 1965, Ser. No. 458,354 8 Claims. (Cl. 28-72) This is acontinuation-in-part of Serial No. 150,320, filed November 6, 1961, nowabandoned.

This invention relates to production of a bulky yarn and fabric. Moreparticularly this invention concerns a drafting procedure formanufacture of a high-bulk yarn of high crimp retention and high crimprecovery adapted for use in fabrics exhibiting a shearling look orinterlocking crimp.

A loopy, bulky surface texture is often highly desirable, particularlyin synthetic fabrics and blends thereof with natural fibers such ascotton and wool, e.g., in items such as rugs and batting. Attempts havebeen made to prepare a fabric characterized by such a surface texture aswell as a high degree of cover or backing hiding power and Wearability,but thus far all such attempts have fallen short of a way of obtaining acombination of all of these desirable features in the same fabric.Therefore it is apparent that the develop-ment of a process forproducing yarn adapted for the manufacture of fabrics which will havethe desired 'bulkiness or fluffiness, high crimp retention, high crimprecovery, high cover, and capability of forming wavelike loops in whatmay be described as a shearling or interlocking-crimp effect representsa highly desirable result. As is known in the rug industry, there is aneed for carpet yarn which will provide more cover or degree of hidingof the backing with the same or less weight of yarn and the ability toform an interlocking or quasi S-shaped parallelized-fiber appearance ofhigh crimp retention and high crimp recovery. After extendedinvestigation we have discovered a simple and economic way tomanufacture such a yarn and fabric prepared therefrom.

This invention has for one object to produce a nonwoven fabriccontaining a bulky, loopy and fluffy yarn of high cover. Another objectis to provide a process and apparatus especially adapted for producingmanmade fibers capable of being formed into a non-Woven fabriccontaining yarn that has good cover, increased strength, high crimprecovery and high crimp retention. A further object is to provide a yarnproduction method comprising successive steps of drafting, crimping,heatsetting and forming filaments into a yarn of high crimp retentionand high crimp recovery after heat treatment. Still another object is toprovide a process and apparatus for producing high-bulk yarn wherein thefilaments are stretched with a relaxing step prior to crimping and thusenabled to be crimped under relatively mild conditions in such a waythat a high-shrink yarn of high crimp retention and high crimp recoveryis obtained after a heatsetting operation. Other objects will appearhereinafter.

As indicated above, it is highly desirable to produce fibers of highcover for a small weight, particularly when a bulky or loopy materialsuch as used in the production of rugs and similar products is desired.Prior-art methods at least about 100 cu. in./lb. after heat treatment.

3,298,079 Patented Jan. 17, 1967 of producing such fiuffable fibersinvolve crimping operations which inherently decrease the strength ofthe fibers and thus make them incapable of forming the highly desirablelasting hand and appearance in the finished piece. Conventional methodsof lofting, entangling individual fibers with one another and crimpinggenerally tend to decrease the strength and durability of the fluffyhighcover yarn desired by the trade.

After extended investigation We have found an apparatus arrangement andmethod whereby the preceding difliculties may be substantially overcomeand a yarn of 2-24 denier per filament, preferably 816 denier perfilament, greater than 12% crimp retention, and a specific volume ofgreater than 100 cu. inches per pound is obtained. We have also found amethod and apparatus for manufacturing pile carpet, the pile or yarn inwhich is characterized by high bulk, high crimp retention and asubstantially parallel fiber arrangement wherein the yarn ends areinterlooped in a snake-like or S-like tortuous path in such a way as toexhibit a permanent nub, all these characteristics resulting from heattreatment, preferably by steaming of said carpet. By high bulk We mean aspecific volume of The yarn of our invention is adapted for formation offabric blends of natural and man-made fibers which exhibit these samehighly desirable characteristics. In a preferred embodiment of theprocess and apparatus of this invention a high bulk yarn is obtained byimparting a the filaments are drafted to from about 100% to about 850%or above), with a relaxing step in which the draft ratio is less thanabout 1, preferably about 0.8 to 0.9. The relaxing step is preferablythe third step of a three-step drafting procedure. The fiber producedhas a shrinkage or shrinkability of 25'75% or higher after drafting andbefore further processing.

By increasing the pressure in the crimping zone we produce a high crimpin the fiber which, even though removed by a certain amount ofmechanical stretching during the subsequent carding and spinningoperations, is re developed by a subsequent heat treatment which mayconsist of steaming, treating with hot water, heating in an oven orpiece dyeing, for example, This heat treatment is characteristic of allembodiment of our invention. The crimping may be improved by guiding thecontinuous filament tow to the crimping zone by passing over and under aseries of guide rolls and providing a widthadjustment arrangementwhereby the tow is kept at a substantially uniform width and thicknessupon entering the crimping zone. Alternatively, a clapper-gatepressurecontrolled mechanism may be set up whereby the crimpingoperation is made substantially self-continuing by allowing the tow tobuild up in the crimping zone in a manner such that sufiicient pressureis produced to cause it to be pushed out at the proper time in auniform, high crimp form.

We have found that our novel operation may be successfully conductedboth when continuous-filament yarn is produced and when the tow is cutinto staple which is further processed by carding, drawing, and roving.The crimp may be recovered or restored and the high bulk imparted byheat treatment of the processed staple fibers or continuous filament tow(for example, with hot water, hot air, or steam) either before or afterthe yarn is tufted into a carpet or converted to a fabric.

We have found the method and apparatus herein described particularlyuseful on modacrylic fibers. These fibers are made from compositionsconsisting of, for example, 40-85% acrylonitrile modified with variousmodifiers and soluble in acetone and dimethyl formamide, for example.Further disclosure of such type of fibers will be had by reference toUS. Patents 2,811,409, 2,831,826 and 2,843,572.

In producing non-woven fabrics from high-shrink or high-bulk yarnaccording to this invention, a more or less tenuous web of looselyassociated textile-length fibers or mixture thereof disposed in sheetform may be produced by carding, garnetting, air-laying, or the like toform an oriented web or batting. In the carding operation Webs are madeby-passing the fiber through a card or other appropriate device to forma web or sheet of loosely associated fibers. A plurality of the webs maythen be superimposed to provide a laminated web weighing from about 100to 5,000 grams per square yard. An oriented web may be converted into afabric by bounding, e.g., impregnating the web with a bonding agent suchas a natural or synthetic resin or spraying a plurality of webs with asuitable plasticizer (115%), e.g., dimethoxyethyl phthalate or triacetinfor cellulose ester fibers, and then heating by passing betweencalendering rolls or through a curing oven.

When cut staple fibers are used in this invention, spinning systems suchas worsted, American, and cotton which parallel the fibers result in thegreatest bulkiness, although woolen system yarns may be prepared havinga lower degree of bulk. The bulkiness may be developed by steaming,piece dyeing, or latex curing of the carpeting. The mild steaming usedin prior-art carpet finishing is insufficient to develop a significantamount of bulk in the yarn. Latex curing at 115' C. or above will do aneffective job of developing bulk. Piece dyeing or skein dyeing willdevelop the bulkiness completely. An excellent Saxony textured carpetcan be made with modacrylic high-bulk yarn without the need for twistsetting. When the carpet pile is steamed, the yarn ends form a permanentnub. Shearing of the pile then gives a Saxony effect which holds itstexture very well in service and in cleaning. We have found that thedesired degree of brightness or dullness of luster may be imparted tothe yarn of this invention by blending bright fibers with dull fibers.When this is done, at least 70% bright fiber should ordinarily be usedand preferably at least from 8590% bright. By our invention in additionto the highbulk, high-crimp retention and high-crimp recovery coupledwith the permanent nub effect, an improved soil resistance is impartedto the yarn. When the product is carpeting, the back or backing suitablycomprises jute, cotton, rayon, nylon, or other appropriate natural orsynthetic fibers as desired. A rubber or latex coating may be applied onthe back of the carpet.

For a more complete understanding of our invention reference is made tothe attached drawing forming a part of the present application.

FIG. 1 is a diagrammatic vertical cross section through a carpet showingthe pile and the back of a product made according to the presentinvention and a prior art product.

FIG. 2 is an enlarged view of the drafting portion of the process withthe details of a preferred embodiment of the drafting operation set out.

&

FIG. 3 is a side elevation view of a crimping step and heat-settingarrangement which may be used in our invention.

FIG. 4 is a block graph comparing the bulked yarn prepared according tothis invention with unbulked yarn.

In FIG. 1, in the prior art carpet, yarn ends 10 are sufficientlystraight, shallow, and far enough apart for the backing 12 to beobserved at some points by one looking downward from above, whereas inthe carpet prepared from high bulk yarn produced using thedrafting-relaxing procedure of this invention the yarn ends 14 areintermingled in a substantially parallel, interlooping or interlockingnodular arrangement in such a manner that the backing 16 is almostsubstantially concealed or covered, it being impossible to look downwardbetween the individual ends, that is, see the backing 16 through theyarn ends 14. This is true regardless of whether a loop-pile or cut-pilecarpet is used, the chief difference being that in the loop-pilearrangement, the yarn ends are continuous in the form of loops ratherthan being cut at appropriate places.

Referring now to FIG. 2, which represents a preferred embodiment of thedrafting procedure of this invention, the tow 18 is passed from spinningcabinets under an idler roll 20 for about of its peripheral surface andthen over and around a preheat roll 22, which may be heated by shoes orother conventional heating means (not shown). The tow should be incontact with the preheat roll 22 for at least 200 degrees of a circularpath. It then passes over and around a first draft roll 24 moving atabout 1.6 times faster than preheat roll 22 in order to provide thenecessary tension for an initial drafting or stretching step. Again thetow should be in contact with at least 200 of a circular path while incontact with said first draft roll 24. Additional tension is thenapplied as the tow moves over a second draft roll 26. The tow shouldagain move over greater than 200 of a circular surface. The tow isdrafted between first draft roll 24 and second draft roll 26 anadditional drafting or stretching of 3.0 to 4.1 more or less above thedraft imposed between preheat roll 22 and the first draft roll 24. Afterleaving second draft roll 26 the tow continues around about 40% of thesurface of a third draft roll 28 moving counterclockwise and opposite tothe direction of second draft roll 26. An additional 1.1 to 1.3 draftmay be applied between the second draft roll 26 and third draft roll 28.

Referring next to FIG. 3, in a crimping zone which may be used in ourinvention, a clapper gate is provided which is controlled by aircylinders in such a manner as to allow the tow to move through thecrimping zone continuously and more or less unrestrictedly, the impartedcrimp being substantially uniform. A plurality of strands of stretchedyarn 30 after passing through yarn guide 35, which aligns the yarn toform a single sheet of parallel yarns, may be moistened by means ofwater or steam spray nozzles 34, which also control the temperature ofthe yarn, prior to being fed into a stulfer box crimper through thebight of feed rolls 36 and 38. The water may applied from a humidifiernozzle. Top feed roll 36 has a straight mechanical linkage (notindicated) to air cylinder 40, which is used to transmit pressure to theroll nip. Feed rolls 36 and 38 operate cooperatively, one being drivenby the other either by gear or surface friction. The stuffer box crimperoutlet 42 is restricted by a clapper gate 44 which is pivoted at point46 and controlled from air cylinder 48. The untreated yarn 30, which is.in the form of a sheet, may pass through a vapor cloud produced by thevapor nozzles 34 prior to passing through the bight of the feed rolls36, 38 and next into the st-uifer box crimping chamber formed betweenwalls 50 and 52. As the yarn passes from the feed rolls 36, 38 into thestutfer box defined by walls 50 and 52, it is heated to semi-plasticityand further moistened by steam which is directed into the stuifer boxthrough inlets 54 and 56. The crimper clapper gate pressure should beless than about 30 p.s.i.g. and the steam pressure at least about 5p.s.i.g The steam admitted through inlets 54 and 56 also heats thestuffer box walls 50, 52. This helps to keep the yarn in a semi-plasticstate during treatment. The heated, moistened, semi-plastic yarn insidethe stuffer box crimping chamber defined by walls 50 and 52 accumulatesand fills the crimping chamber in a configurated mass 58 which exerts apressure on the clapper gate 44. When the mass pressure equals orexceeds the pressure produced by the air cylinder 48 operating on theclapper gate 44, the configurated yarn 60 then flows out of the stuiferbox crimper restriction 42 to fall freely on a variable speed endlessconveyor 64 and be carried through a drying or heat-setting chamber 66in which the moist, hot yarn, now crimped and curled, is dried to aheat-set form 68 in a high amplitude, low frequency, crimped and curledstate. The treated, heat-set, and dried yarn 68 upon leaving the heatingchamber 66 may be removed from variable'speed endless conveyor 64 bymeans of a plurality of mechanical packaging devices such as parallelpackage winders 70. Packaging devices 70 could also be a beamer or aball-warping apparatus or a baling device which would package aplurality of the yarns after treatment. The yarn could also be formedsubstantially directly into a non-woven yarn fabric, tufted into acarpet after plying and coning, or cut into staple fibers to be furtherprocessed.

It is sometimes helpful to apply a stream of air against the yarn 60just as it leaves the crimping chamber restriction 42 to immediatelycool the yarn and direct it toward the endless conveyor 64. A finishingagent may be applied to the yarn prior to packaging or furtherprocessing.

The air pressure (p.s.i.g.) at air cylinder 40 is adjusted to exert suchpressure between rolls 46 and 48 as to prevent yarn slippage. Thepressure applied to the clap per gate 44 is adjustable to obtain thedesired amount of kinkiness of crimp in the yarn. Higher pressuresproduce a higher frequency, sharper crimp or curl. The pressureapplication at the air cylinders may also be accomplished in other ways,e.g., by dead weights, hydraulic devices, and the like.

The amount of moisture which may be applied to the sheet of yarn 30 fromvapor nozzles 34 will control the hold-up time factor and temperaturefor the heat setting and drying of the yarn within the heat-setting anddrying chamber 66.

FIG. 4 will be described in connection with Example VIII hereinafter.

A further understanding of our invention will be had from aconsideration of the following examples which are set forth toillustrate certain preferred embodiments.

EXAMPLE I A spinning solution consisting of 19% of modifiedacrylonitrile polymer containing about 60% acrylonitrile and about 40%vinylidene chloride polymer modifier with an average molecular weight of50,700 dissolved in dimethyl formarnide to give a solution having aviscosity of 1020 poises at 100 C. was converted into filaments in aplurality of spinnerettes. A more complete description of such anoperation may be found in HS. Patent 2,811,409. The spinnerettes were 3inches in diameter, and each contained 300 holes of 0.20 mm. indiameter. The top air temperature was 501-5 C. and the bottom airtempera 5?;15015" C. in the spinning cabinet.

45 cabinet ends of tow were passed continuously from the spinnerettes ata rate of 19.3 meters per minute (m./m.) and treated with mineral oilbase lubricant. The denier per filament of the tow was 16. The tow wasthen drafted on a series of 5 rolls such as those illustrated in FIG.2.The first roll was an idler roll turning counterclockwise. The secondroll or first draft roll moved clockwise, the tow passing over andaround 60% of the surface thereof. The second and third draft rollsmoved respectively counterclockwise and clockwise, the tow being incontact with the former 60% and the latter 30% of the surface thereof.The draft. ratio between the preheater roll and the first draft roll was1.6:020. The draft ratio is the ratio of the length of the same portionof the yarn after stretching to the length before stretching or,expressed in another way, the rate of the draft roll r.p.m. to thepre-draft r.p.m. Between the second draft roll and the preheater rollthe draft ratio was 48:0.20 and between the third draft roll and thesecond 0810.20, the total draft ratio being 56:06. This amounts to about500% tension or stretching in terms of percent increase in length. Thepreheater and first two draft rolls were kept at the followingtemperatures by the use of a Dowtherm heat exchange agent.

Dowtherm Temp.

Preheater 255i5 C. First draft roll 240il0 C. Second draft roll 210110C.

The tow was next passed through a crimping zone such as that of FIG. 3where a substantially uniform crimp of 7 crimps per inch (c.p.i.) wasimparted. Crimper conditions were as follows:

After leaving the crimping zone the tow was conducted through a drying,shrinking and heat-setting zone heated to a temperature of from C. to C.for a hold-up time of 3 minutes. The fiber after being heat-set had thefollowing properties:

Instron, g.d. 0.65 Elongation percent 3 0 Crlmp c.p.i 15

Denier per filament (d./f.) 16

EXAMPLE II A modified acrylonitrile yarn was prepared in accordance withthe general procedure of Example I, except that the solvent used inspinning this time was acetone, and the yarn cut into staple fiber. Thestaple fiber was stock dyed in a Riggs and Lombard dye kettle at 71 C.with a basic dye formula in a medium brown shade. The staple was thendried at 104 C. on a belt-type dryer. The staple was then processed in a2 /2s 3-ply yarn on the following equipment:

(1) Whitin roller card (2) Warner Swazy pin drafter (3) Whitin drawframe (4) Whitin roving frame (5) Whitin twister The spun yarn was madewith four turns per inch (t.p.i.) in the singles and 2 /2 t.p.i. in theply. Skeins of this yarn were tested and found to have a specific volumeof 75 cubic inches per pound. The skeins were treated in steam at 100 C.at atmospheric pressure. Specific volume after treatment was found to be115 cubic inches per pound. The skeins were then tufted into ahigh-bulk, high-cover cut-pile rug. Steaming of a modacrylic yarnprepared by a prior art lower-drafting and unmodified crimping andheat-setting procedure employing none of the novel techniques of thepresent invention caused an increase in specifi volume of the yarnskeins of from 75 to 85 cu. in./ lb. only.

EXAMPLE III Skeins before steaming made by conditions described inExample II were tufted in a cut-pile rug construction. Steaming of therug caused the fiber to bloom into a highbulk yarn. A 25-ounce rug madefrom this high-bulk yarn was found to be equivalent in bulk or loft to a32- ounce rug produced from yarn formed without the special high-draft,no-relaxing, substantially self-imposed crimping of the presentinvention.

EXAMPLE IV Skeins made from fiber produced at plant conditions describedin Example II were made up in natural yarn form and tufted in aloop-pile rug construction at 3 ounces per square yard. This rug waspiece-dyed at 71 C. with a grey premetallized dye formula and then driedat 104 C. During the dyeing and drying operations, the bulk wasdeveloped in the carpet. The carpet was of high bulk and free fromdefects. A carpet made from yarn produced by prior art stretching andrelaxing techniques followed by mechanical crimping under 30-60 p.s.i.without the use of banding guides or clapper gates was of anunattractive, non-durable appearance having cracks in the pile, laydownof individual loops or substantially no interlooping bulkiness, andcould not be successfully piece dyed.

EXAMPLE V A comparison was made by preparing 2 high-bulk staple-yarnsamples. The samples were prepared by a process wherein double draftingwas followed by a relaxing step, with especially harsh crimperconditions employed. For these samples substantially the same processwas used as in Example I. Table I which follows gives the comparativeresults.

Table 1 Sample 1 Sample 2 Number cabinet ends in tow 45 45 First draftratio 1. 6 1. 6 Total draft ratio 4. S 4. 8 Draft or relax ratio .90 9OPreheat temperature (Dowthenn), C 255 255 Draft temperature (Dowtherm),C. 240 240 Relax temperature (Dowtherm), C 200 200 Steam rotameter RD G(Orirnper) 5. 24 Steam pressure (Crimper chamber) 50 50 Crimperdischarge temperature, 0.. 85 95 Crimper clapper gate pressure 26 10. 5Heat set crimped, d./f 13. 8 17. 5 Heat set ribbon, d./i. (no crimp)12.0 12. 9 Percent Crimp recovery on steam G. 9 16. 5 Crimps per inch(heat set tow) 11. 9 10. 7 Strength of heat set tow, g./d 0. 43 0. 45Percent Gain in crimp recovery". Percent Gain in strength Hot watershrinkage (before heat setting) 18 19. 5

Total draft ratio including the draft between the second and third draftrolls.

In the samples 1 and 3 in Table 1 the item marked draft or relax ratiois the relax ratio between rolls such as 26 and 28 of FIG. 2. Thecompositions used in this comparison were modaerylic polymer towprepared as in US. Patent 2,811,409, the polymer having an acrylonitrilecontent of approximately 65% EXAMPLE VI Heat-set tow was preparedsubstantially as in Example I, using a clapper gate modification of theclapper gate stufier box-type crimper such as that depicted in FIG. 3.The yarn and treating conditions were as follows:

Yarn2200 denier, 16 cl./f., brown, continuous filament lofted acetatetwisted and piled to about 6600 denier with 6Z turns per inch.

Feed roll speed 50 m./m, Feed roll air pressure 1 A p.s.i.g. Moisteningair pressure 10 p.s.i.g. Clapper gate air pressure 5 p.s.i.g. Steampressure 3 /2 p.s.i.g. Oven temperature C.

The treated, textured yarn was subsequently tufted into a rug withA-inch cut-pile height weighing about 32 oz./sq.- yd. (tuft weight). Theresulting appearance and texture were excellent, with the highlydesirable surface loopiness or interlooping clearly exhibited, includinga high retentive crimp,

EXAMPLE VII The procedure of Example VI was followed with the exceptionof the following:

Yarn3 ends of 3-plied 2200 denier, 16 d./f., brown continuous filament,lofted acetate, 6Z turns per inch a total of about 20,000 denier Feedroll speed 50 m./m. Feed roll air pressure 2 p.s.i.g. Moistening airpressure 15 p.s.i.g. Clapper gate air pressure 7 /2 p.s.i.g. Steampressure 5 p.s.i.g. Oven temperature C.

The treated, textured yarn was subsequently tufted into a rug withit-inch cut-pile height weighing 32 oz./ sq. yd. The enhanced loopiness,good cover, bright color and crimp recovery and crimp retention wereagain clearly exhibited.

EXAMPLE VIII The increase in specific volume brought about by subjectionto steam was measured for three yarn samples, viz., 1) a prior artmodacrylic yarn prepared by conventional stretching, relaxing, anddrying low-shrink meth ods, (2) a high-shrink unmodifiedpolyacrylonitrile yarn and (3) a high-shrink modacrylic yarn, the lattertwo prepared by the high-shrink, high-bulk process of this invention.The results are shown in FIG. 4. The increase in specific volume togreater than 100 cu.in./lb. upon bulking by heat treatment is evidencedby the two samples prepared according to this invention, particularlythe modacrylic sample.

EXAMPLE IX In this example the effect of steaming and aging on thespecific volume of modacrylic yarn produced in accordance with thepresent invention yarn is demonstrated. The crimper pressure and thesteam pressure in the crimping zone are increased in some instances. Theresults of 3 /2 months aging are indicated in the following chartwherein 8 samples are compared as to percent increase in specific volumeupon steaming both before and after aging. The example indicates thecrimp retention or lasting bulkiness of our yarn.

Eflect of 3 months aging on specific volume tests on steamed modacrylicyarn Sample No 1 2 3 4 5 6 7 8 Crimper pressure (p.s.i.g. 15 6 6 15 15 66 Steam pressure (p.s.i.g.). 6 7O 6 6 6 70 70 70 Relax temp. C 190 190190 240 240 240 240 190 Draft temp. C ,1 210 190 190 210 190 210 190 210SPECIFIC VOLUME TESTS (.05 GJD TENSION) In. /lb., initially on /1 yarn:

Unsteamed 69 77 71 70 70 75 73 75 Steamed 111 110 108 104 104 114 109108 Percent increase 38 34 33 33 34 33 31 In /1b., aged 3% months on2.5/3 yarn:

Unsteamed 82 9O 79 79 83 82 79 81 Steamed 121 110 104 100 111 110 109106 Percent increase 32 18 24 21 25 25 28 24 EXAMPLE X This exampleillustrates the use of the high bulk yarn of this invention in a blendwith a natural fiber. A 28- oz. per sq. yd. loop-pile carpet was tufted.After tufting, the carpet was steamed and examined for bulk, cover, handand appearance. The characteristics of the sample, including thespecific volume before and after steaming are shown in the followingtable. Again it can readily be seen that the specific volume aftersteaming is considerably over 100 cu. inches per pound. The modacrylicyarn used in the blend of this type was produced by the increasedcrimper steam and pressure conditions in the above-described process.This sample exhibited excellent cover, good hand, high crimp, high bulk,and fluffy appearance.

Percent High-bulk modacrylic 71.5 Percent Wool 28.5 T.p.i. Singles, Z4.5 T.p.i. Ply, S 2.6 Denier 4600 G./D. .66 Percent Elongation 28.9Specific volume, in. lb. (.05 g./d. Tension) Before steaming 96 Aftersteaming 107 Percent Increase 11 /z EXAMPLE XI A comparison of variousmethods of bulking by heat treatment to produce the high bulk, highcrimp retention yarn of this invention was made. Six-inch stock-dyedmodacrylic carpet samples were heat treated in the following ways.

(1) Latex, air-cure (control) (2) Latex, oven-cure face up at 121 C.

(3) Latex, oven-cure face down at 121 C.

(4) Latex, surface spray with water, oven-cure face up at 121 C.

(5 Steam on Hoffman press latex, air-cure (6) Mock piece dye, latex,air-cure (7) Wet out, tumble dry at 82 C. latex, air-cure (8) Latex,oven-cure face down at 82 C.

All types of heat treatment were satisfactory, the steaming on theHoffman press giving what appeared to be a somewhat better developmentof bulk than the other types, with curing in the oven face down at 121C. giving second-best results. Piece dyeing was also highly satisfactoryin imparting the desired loopy high bulk.

The results indicated that there is an apparent dulling of the fiberwhen the high-bulk crimp is developed upon heat treatment, this dullingimparting improved resistance to soiling over yarn produced by prior artprocedures.

EXAMPLE XII An evaluation was made of modacrylic fibers of from 8-16denier per filament, high-bulk yarn produced in accordance with thepresent invention. 20 pounds of each of 3 lots of 8, 12 and 16 d./f.respectively were processed on a roller card and pin drafted into 50grain slivers of 4 inches in length. The 12 d./f. fibers were processedextremely easily. However, 8 d./f. and 16 d./f. extremities were foundappropriate, since the 16 d./f. fibers exhibited a small tendency to notdetach quite so readily from the surface of the roller and the 8 d./f.denier fibers barely maintained a cu. inch per lb. specific volume orrepresentative high bulk after steaming. The fibers were pin drafted andprocessed into a 2.5 1 cc. yarn with a 2.5 TM, which is a representativecarpet yarn. Several finer-count yarns were also spun from each of thefibers approaching the spinning limit of each denier, viz. for 8 d./f.,16/1 00.; for 12 d./f., 12/1 cc. and for 16 d./f., 6.1/1 cc. As thecounts approached the fine extremity a slight cockling or non-uniformeffect was detected, indicating that the limit of fineness was beingapproached. Yarn was spun using twist multifilament of 2.0, 2.5, 3.0 and3.5, indicating that substantially any degree of twist could be insertedin the yarn without decreasing the desired bulk development. Thefollowing table indicates the results of evaluation of separate lots of8, l2 and 16 d./f. modacrylic high-bulk yarn of this invention. Part ofthe yarn was skeined and steamed on a Hoffman press and the specificvolume in cubic inches per pound of the steamed and unconditioned yarndetermined.

Evaluation of 8, J2, and 16 d./f. modacrylic high-bulk yarn Ratio avg.specific volume before/after steaming on Hoffman press Percent ncreasein bulk Length 0 0 From an examination of the above table it can be seenthat the carpet yarns of all the samples produced the increase in bulkby which yarn prepared according to this invention is typified. The 16d./f. yarns developed high bu-lk all the way from a 25/1 cc. yarn tonear a denier per filament spinning limit of 6.6/1 cc. The higher thetwist, in general, the more difficult became the development of bulk.

EXAMPLE XIII This example illustrates that loop pile carpets made fromhigh bulk modacrylic fiber prepared in accordance with this inventionmay be stock dyed or piece and dried in such a way as to produceimproved cover and soil resistance. A quantity of 16 d./f., 4" brighthigh-bulk modacrylic staple was stock and piece dyed under theconditions of the following table with the crimp-retention, high-bulkretention, and wear-resistance as indicated therein.

Carpeting tests D./f. x length 16 x 4 Luster Bright Stock dyeingtemperature, C 71 88 }Piecc Dyed {Undyed Undyed Stock dryingtemperature, C 03 93 at 71 C. Steamed Unstcarned Yarn counts TPIsingles/ply Denier singles GJd. singles Percent elongation singles HotWater shrinkage Specific volume tests, ind/lb Original Floor test:

Initial thickness Percent thickness retained 10,000

steps Percent thickness retained 20,000

steps Stair test, down flight:

Beginning wear Moderate wear Severe wear;

Table leg test, 100 ps. Initial thickness. Percent thickness min.recovery h 52 52 Percent thickness retained, 24.

hr. recovery 67 67 In the preceding table, in addition to a showing ofhigh bulk and good wear, is seen a heat and moisture shrinkage ofapproximately and an increase in specific volume of up to 50% in highbulk yarn spun on an American system.

EXAMPLE XIV Crimp reten- Nominal tion, percent Steam/Chamd./I. x lengthber, p.s.i.

It can be seen from the above table that a minimum crimp retention ofabout 12% is characteristic of the heat-treated high-bulk yarn preparedaccording to the present invention.

EXAMPLE XV Continuous filament textured yarn was prepared in accordancewith the embodiment of this invention wherein the crimping pressure andsteam pressure in the crimping zone were increased and the filamentswere twisted slightly prior to the crimp-operation. The yarn had a totaldenier of 2700. The drafting operation was conducted on an apparatussuch as that shown in FIG. 2 with the second and third drafting rollsoperated respectively as relaxing and take-up rolls. The variousspinning, twisting, crimping, and heat-setting or drying conditions wereas follows- Speeds: m./m. Preheat roll 43.5

Draft roll 68.6

Relax roll 202 Take-up roll 186 Draw roll 188.5 Crimpcr 182 Draw roll112 Draw roll 113.5

Temps: C. Preheat 185 Draft 202 Relax 180 Dryer 1st stage Dryer 2ndstage 141 Spinning machine: C. Bottom air temp. 154 Top air temp 51Crimper: p.s.i.g. Chamber pressure 19 Spray pressure 19 Roll pressure2.5

A qualtity of this 2700 total denier, bright-textured filamentmodacrylic yarn of 14 denier per filament was package dyed nutria anddark brown by a commercial dyer. The yarns were plied with 1.0 t.p.i.(turns per inch) and as follows:

1 end of nutria with 1 end of natural 1 end .of brown with 1 end ofnatural 1 end of nutria with 1 end of brown The yarn was combed up onthe gauge tufting machine to make the following samples.

Sample 1.A1ternate ends of 2700 denier 2-ply nutria and natural, andnutria and brown, tufted into 7 pile bright, 25 oz./yd. loop-pilecarpet.

Sample 2.2700 denier, 2-ply in the following arrangement:

1 end natural/nutria 1 end nutria/brown 1 end natural/ brown 13 Theseyarns were tufted into A pile height, 22 oZ./yd. loop-pile carpet.

Both these carpets had excellent bulk and cover. The 22 oz./yd. carpet,Sample 2, had approximately equal bulk and cover to a 25 oz./yd. staplemodacrylic carpet of comparable pile height.

EXAMPLE XVI Several pounds of 3 d./f., 1-2-inch prestretched modacrylicyarn were carded into oz./yd. batting of (1) 100% modacrylic and (2) 50%blend of modacrylic with polyethylene. The batting was subjected to twotypes of heat treatment, viz. (a) steam in an open Hoffman press withthe batting unrestrained for 30 seconds at 146 C. and (b) dry heating ina glass radiant press using no pressure and with batting for 4 minutesat 177 C. The application of heat to the unrestrained batting resultedin considerable shrinkage and high bulk, particularly at the extremeedges of the batting where the fibers were more loose and fluffy.Batting of 1 6 d./ f. modacrylic high-bulk fiber similarly made whichhad not been prestretched exhibited even more shrinkage and bulkdevelopment than the 3 d./f. fiber.

EXAMPLE XVII This example demonstrates the effect of drafting the samemodacrylic yarn at a ratio of 1.0 or higher and less than 1.0, viz.,about 0.85. The following table presents the results on yarn thusdrafted. The drafting step for which the data for the samples of thefollowing table were obtained was substantially the third step of athreestep drafting process such as depicted in FIG. 2, specifically, thedrafting step between second draft roll 26 and third draft roll 28. Asindicated in the table a comparison was made between heatset andunheatset yarn.

a way of manufacturing a yarn of surprising high bulk and strength withan enhanced crimp permanency or crimp retention. This high bulk andhighly retentive crimp results at least in part from a high-d-raftoperation which includes a relaxing step. The overall result is astronger yarn with much less harsh and plastered filaments. A shrinkageof 3060% is often obtainable by the heat treatment step as well as anincrease in specific volume to at least 100 cu.in./lb. Without theapplication of the high draft-relaxing step, preferably coupled with thehigh pressure crimping techniques and heat-treatment or bulking step,the crimp uniformity and strength generally decrease rapidly with anincrease in crimps per inch. Thus, when the technique of controlling thedraft and including a relaxing step is followed by imposing fewer crimpsper inch in the crimping zone to obtain a high-shrink yarn, a highcrimp-per-inch value in the yarn is obtained upon subsequent shrinkingby heat treatment, prefer-ably steaming, together with an enhanced crimpretention.

We do not wish to be bound by any particular theory as to the cause ofthe ability of the high-bulk yarn of this invention to shrink whensubjected to elevated temperatures after textile processing. However, itis possible that this high-bulk, high crimp recovery characteristic isdue to (l) a tendency of each individual fiber to revert when heated tothe orginal high-crimp configuration lost to a certain extent in themechanical stretching action of drawing, carding, and the like whenstaple fiber is used or (2) to an actual imparting of an added crimp inthe shrinking action upon heating as a result of the preceding steps ofa high degree of stretching with negligible relaxing and without aseparate relaxing step and a mild uniform width and thickness crimpingoperation when continuous filament yarn is used. This shrinkage orbulking with resulting high crimp recovery and high crimp reten- Percentshrinkage vs. relax ratio modacrylic yarn Heatset 1 Unheatset DraftPercent Test ratio Tenacity Percent Percent Tenacity Percent PercentShlll'lk (grams/ elongation at hot water Denier (grams/ elongation atModulus of hot water Denier age 2 denier at break Shrinkage denier atbreak elasticity shrinkage break) break) Average 0.85 1. 77 39. 2 0.0 2,450 1.82 29. 0 40. 4 11. 6 2, 090 17. 2

Average- 1. 0 1. 62 37.8 0. 27 2, 840 1. 89 17. 6 48. 4 22. 1 2, 003 4].8

1 At 140 C. for 5 minutes after drafting.

From the preceding tabular results comparing a thirdstep drafing at aratio of 1.0 with one at a ratio of less than 1, specifically, 0.85, itis apparent that the following advantages are obtained by use of a ratioof less than 1.0.

(a) The unheatset fiber has a higher elongation (30% versus 18%). Thismakes the fiber tougher and better able to stand crimping, texturizing,or the like.

(b) The hot Water shrinkage is lower (11.6% versus 22.1%). This meansthat the fiber shrinks less in subsequent treatments. As shown by aheatset fiber with 140 C. heatsetting, this amounted to only 17%shrinkage during heatsetting versus 42% using the 1.0 ratio.

(c) The final properties of the fiber were as good or 7 better afterheatsetting.

((1) By using the same manufacturing process, a lower d./f. fiber can beproduced after heatsetting due to the lower shrinkage duringheatsetting.

It is believed that it can readily be observed by the precedingdescription and examples that we have invented effected within thespirit and scope of the invention as described hereinabove, and asdefined in the appended claims.

We claim:

1. A method for preparation of a. high-bulk modacrylic 0 yarn productwhich comprises spinning a modacrylic yarn of 2-24 d./f., drafting theyarn at a draft ratio of from about 2:1 to 8.5 :1 by passing over aseries of draft rolls arranged to draft the yarn in at least threestages the last of which is at a draft ratio of less than about 1.0,steam crimping the drafted yarn at a clapper-gate pressure of less thanabout 30 p.s.i.g. and a steam pressure of at least about p.s.i.g.,conducting the yarn in a substantially tensionless condition into aheat-setting zone and forming the yarn into a high-bulk staplemodacrylic yarn.

2. The process according to claim 1 wherein the draft ratio of less thanabout 1.0 is between about 0.8 and 0.9.

3. A method for the preparation of a high-bulk yarn product whichcomprises extruding a plurality of continuous modacrylic filaments of2-24 d./f., drafting the filaments over a series of draft rolls in atleast three stages, the third stage of drafting being at a ratio of lessthan 1, crimping the drafted filaments and heating and moistening themwith high-pressure steam while they are compressed in a crimping zoneunder less than 30 p.s.i.g. clapper-gate pressure and at a steampressure of at least about 5 p.s.i.g., removing the steamed filamentsfrom the crimping zone so that they fall of their own weight on a movingsurface, conducting said filaments on said moving surface in atensionless manner through a heat-setting zone having a temperature ofat least 100 C. for at least 3 minutes and cutting said filaments intostaple fiber lengths, processing said cut filaments into a staple yarnand subsequently subjecting said yarn to treatment with steam to developa high degree of bulkiness and crimp.

4. The process of claim 3 wherein the first stage of drafting has aratio between 12:1 and 2:1, the second stage of drafting has a ratiobetween 2:1 and 5: 1, and the third stage of drafting has a ratiobetween 08:1 and 1.0: 1.

5. The process of claim 3 wherein the filament-s are subjected to asteam pressure in the crimp zone of greater than p.s.i.g.

6. The method of claim 3 wherein the staple yarn is subjected to thefinal steaming treatment after being processed into fabric form.

7. The method of claim 3 wherein the 3-stage drafted, steam-crimped,heat-treated cut staple is processed into a yarn and further processedinto a pile floor covering, and the final steaming treatment is thencarried out.

8. The method of claim 3 wherein the 3-stage drafted, steam-crimped,heat-treated cut stalple is processed into a non-woven fibrous battingand subjected to a final steaming treatment to enhance its bulk andloftiness.

References Cited by the Examiner UNITED STATES PATENTS 2,669,001 2/1954Keen 28--72 2,686,339 8/1954 Holt l966 2,917,806 12/1959 Spence et a1.

3,017,684 1/1962 Pittman l966 X 3,024,517 3/1962 Bromley et a1 l966 X3,101,521 8/1963 Rosenstein et al l966 X 3,142,147 7/1964 Betsch 57157 XROBERT R. MACKEY, Primary Examiner.

DONALD W. PARKER, Examiner.

1. A METHOD FOR PREPARATION OF A HIGH-BULK MODACRYLIC YARN PRODUCT WHICHCOMPRISES SPINNING A MODACRYLIC YARN OF 2-24 D./F., DRAFTING THE YARN ATA DRAFT RATIO OF FROM ABOUT 2:1 TO 8.5:1 BY PASSING OVER A SERIES OFDRAFT ROLLS ARRANGED TO DRAFT THE YARN IN AT LEAST STAGES THE LAST OFWHICH IS AT A DRAFT RATIO OF LESS THAN ABOUT 1.0, STEAM CRIMPING THEDRAFTED YARN AT A CLAPPER-GATE PRESSURE OF LESS THAN ABOUT 30 P.S.I.G.AND A STEAM PRESSURE OF AT LEAST ABOUT 5 P.S.I.G., CONDUCTING THE YARNIN A SUBSTANTIALLY TENSIONLESS CONDITION INTO A HEAT-SETTING ZONE ANDFORMING THE YARN INTO A HIGH-BULK STAPEL MODACRYLIC YARN.